[1] The Bubble System introduced a unique new form of data storage for arcade-style video games.
There was a separate Zilog Z80 for sound control, which drove two AY-3-8910s, a custom Konami SCC (K005289), and a Sanyo VLM5030 speech synthesizer.
It was considerably more expensive than ROM chip-based boards and extremely sensitive to electromagnetic fields that could render the game unplayable.
Most games on this system were eventually ported to standard ROM chips, and it was discontinued.
Konami has made homages to the Bubble System in several games; with the Morning Music being one of the playable tracks in Keyboardmania[1] and NOSTALGIA[2], and the intro of Konami Classics Series: Arcade Hits featuring the song too.